Few people slaying the 270 figure mentioned by the op and mileage issues
I have done 45k in 15 months, 20k of those miles running 240@stage1 and 20k running 280@stage2+, consistently running 280 on 2 different rolling road days, latest results were down at 270 but thats because it is overdue its 10k service and should easy get those 10 ponies back. Also my car has done 105k in total now and not missed a beat reliability wise.
Ed30 would be the realistic way to go and with a WALK kit and Stage1 map you will have a beast, go to Stage2+ and you will have a monster.
If I am running 280bhp and am picking off bigger cars than the R32 then you probably are not running 270 as stated... If you crave power why not just tune up the GTI properly to Stage 2+. Below is my graph on 105k done last week